How do bed sores happen?

Bed sores, also known as pressure ulcers or decubitus ulcers, are areas of skin damage that result from prolonged pressure on the skin. These sores are commonly seen in patients who are bedridden or wheelchair-bound and are unable to change their position frequently. Bed sores can be a painful and serious issue that can lead to severe infections and, in some cases, even death. It is essential to understand how bed sores happen to prevent them from occurring and to ensure proper treatment.

What are Bed Sores?

Bed sores are a type of injury that occurs when there is prolonged pressure on the skin. They commonly occur in bony areas where the skin is thin and where there is minimal fat or muscle, such as the heels, hips, sacrum, and elbows. When there is constant pressure on the skin, the tissues in the area lose their blood supply, leading to tissue damage, and eventually, tissue death. The skin in the affected area may turn red or purple and may eventually become blistered, open wounds or ulcers.

Causes of Bed Sores


The leading cause of bedsores is pressure. When you stay in the same position for several hours, the pressure on the skin and underlying tissues can reduce blood flow to the area, resulting in skin damage.

Shearing force:

This type of force occurs when the skin of a person moves against the bed or chair surface due to gravity or people moving them. This movement causes damage to the blood vessels and tissues leading to bedsores.


Friction injuries can also contribute to bedsores. When the skin rubs against a surface, the outer layer of the skin can abrade, causing tissue damage.

Risk Factors for Bed Sores


Patients who are bedridden or wheelchair-bound for extended periods of time are at higher risk of developing bedsores. The longer the person remains immobile, the more likely it is that bedsores will develop.


Elderly people are more susceptible to bedsores due to thinning of the skin and decreased skin elasticity.

Medical Conditions:

Several medical conditions can increase a person’s risk of developing bedsores, including diabetes, circulation problems, and malnutrition.


Prolonged exposure to moisture from urine or feces can irritate the skin and increase the risk of bedsores.

Decreased Sensation:

Patient’s who have a decreased sensation in the affected areas due to nerve damage is also considered as risk factors in developing bedsores as they may not feel pain or discomfort in these areas, reducing the ability of a person to change position.

Stages of Bed Sores

Stage I:

The initial stage of a bedsore is characterized by skin discoloration, usually over a bony area. The skin may feel warm or cooler than the surrounding skin and may be painful.

Stage II:

At this stage, the injury affects the deeper layers of skin, causing the skin to break, leading to an open wound. The wound may appear as a blister or shallow crater.

Stage III:

The sore has now progressed, affecting the deeper tissues, including the fatty tissue. The wound may appear as a crater with a depth of about a few centimeters.

Stage IV:

This is the most progressed stage of the bedsore. The sore has now spread into the muscle and bone tissues, affecting the joint areas, and may cause permanent damage.

How to Prevent Bed Sores

Regular Repositioning:

It is essential to change a patient’s position at least every two hours. Regular repositioning of the patient can help relieve pressure on the skin and prevent the formation of bedsores.

Use of Supportive Surfaces:

Using special supportive mattresses or cushions can help reduce pressure on bony areas and, therefore, reduce the incidence of bedsores.

Skin Care:

Maintaining good skin hygiene is essential in preventing bedsores. Clean and dry skin is less likely to develop skin breakdown.

How are Bed Sores Treated?

The treatment for bedsores varies based on the stage of the wound, the level of pain, and the presence of any underlying medical conditions. Treatment may include:

Wound Care:

Cleaning the wound daily, and applying a dressing to improve healing, reduce pain, and protect from further injury.


For advanced stages of bedsores, surgical intervention may be necessary to close the wound, clean the area to prevent infection and promote healing.


Pain medications, antibiotics or other medications may be helpful in managing pain and preventing infection.


Bedsores are a painful and serious condition that can occur in patients who are immobile or wheelchair-bound for long periods. Understanding the causes, risk factors, and stages of bedsores is essential to prevent their occurrence and to ensure proper treatment.

Questions and Answers:

  • What are bed sores?
  • Bed sores are areas of skin damage that result from prolonged pressure on the skin.

  • What causes bed sores?
  • The leading cause of bedsores is pressure, along with shearing force and friction.

  • What are the stages of bed sores?
  • Bed sores have four stages: stage I – initial stage, stage II – affecting the deeper layers of skin, stage III – affecting deeper tissues such as fatty tissue, and stage IV – most progressed stage that affects bones and muscles.

  • How can bed sores be prevented?
  • Bedsores can be prevented by regular repositioning of the patient, using supportive surfaces, and maintaining good skin hygiene.

  • How are bed sores treated?
  • Bed sores are treated by various methods such as wound care, medications, and surgery for advanced stages.


  • Mayo Clinic. (2021). Bed sores (pressure ulcers). Retrieved 7 June 2021, from
  • Medline Plus. (2021). Pressure ulcers. Retrieved 7 June 2021, from
  • National Institute on Aging. (2020). Bed sores (pressure sores). Retrieved 7 June 2021, from